半溶融凝固法により製造したAl-7%Si-0.5%Mg合金の微細組織と機械的性質 [in Japanese] Microstructure and mechanical properties of an Al-7%Si-0.5%Mg alloy produced by semi-solid process [in Japanese]
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Microstructure and mechanical properties of an as-cast and heat-treated Al–7%Si–0.5%Mg– alloy (an alloy A357) produced by both the conventional mold casting and semi-solid process have been investigated. The effect of microstructural changes during heating to semi-solid temperatures on the mechanical properties are also discussed for the alloy produced by the semi-solid process. The microstructure of the produced alloy basically consists of the spherical α phase and fine eutectic silicon phase without any segregates and defects. The average size and volume fraction of the α phase are about 52 μm and 65 ±3%, respectively. The eutectic silicon phase becomes spheroidized by solution heat treatment. The ultimate tensile strength and elongation of the peak-aged alloy are 350 MPa and 16%, respectively. As the heating and holding times increase, the mean particle size of the α phase slightly increases. The increment, however, is negligibly small in the examined condition. Therefore, the mechanical properties of the alloy produced by the semi-solid process remain almost unchanged with increasing heating and holding times, compared with those of the non-heated alloy. Coalescence between α phase particles occurs with increasing heating and holding times, resulting in the shape change of the particles.
- J. Japan Inst. Light Metals
J. Japan Inst. Light Metals 48(7), 329-334, 1998-07
The Japan Institute of Light Metals